The title of this was going to be much shorter a few days ago... recent problems and setbacks changed that and I decided to show more of what I've gone through trying to get this project completed.
This all started with a bike training stand a friend gave me. I already have a pedgen, described elsewhere on this site. It looks like this:
It's not huge but it's not what I'd call portable... I figured one made using the training stand would be a little easier to move around.
The same friend called one day about a piece of electronic equipment a client of his wanted out of her attic. He told me it had "Back UPS PRO" on the front... I said I'd take it.
The UPS had been sitting in the attic without power for at least 5 years but it still worked and the CSB 12ah battery even came around and seems to still hold close to the original 12ah.
With the trainer and UPS... I decided to build a complete system... with an eye toward selling it.
Here's the training stand, it's a Performance Travel Trac. A magnetic resistance, friction drive affair.
I have a few "big" PM DC motors around here. The first candidate was a motor from a handicap scooter.
I could never find any information on the motor. It came out of an Ortho-Kinetics scooter and is marked "Redmond PV2R08R 24VDC".
The way it moved the scooter around, my guess is it is a 400-600 watt motor.
I first set it up as a friction drive using the trainer's roller and bearings.
All the gray blocks you see are pieces of Trex plastic decking. I have a few pieces of scrap that I've used for a few different things over the years... they seem to make a good coupler but I went through that many trying to get a coupling that would run true.
Part of the problem was that the trainer's roller was a different size from the motor and was threaded. Once I had a hole drilled all the way through the block and then threaded it onto the roller, the hole on the other side wouldn't be centered.
To solve this I ended up drilling a hole just long enough for the threaded part of the roller and then hooked up a drill to the roller and lathed a "true" hole on the other end.
The member that the motor sits on was part of a frame from a very old microwave oven.
The motor originally had a plastic cog drive for a cogged rubber belt and a flat side with a hole for a drive pin. To keep the length of the unit down, I cut off some of the shaft and drilled another hole for a drive pin.
Here's a close up of that with a temporary pin made from copper wire.
I cut down a fan from a microwave oven, added some tabs to the mounting rail to hold the motor... and had to make another coupler when the first one started running out of true!!!
I ended up using a through bolt for a drive pin and left the coupler square both for strength and for ease of removal using a wrench.
I melted and formed a cowling from a piece of Plexiglas from yet another microwave and added a diode and cigarette lighter socket to the motors wires.
This looked good and seemed to work OK although I wasn't too happy with the friction drive.
The output was fine at 3amp but trying to get anything above that resulted in extreme slippage. The torque for the friction drive is supplied by a spring and I found that the triangle formed once you have the drive engaged (see the third picture above) was just about the right size to stuff a tennis ball into to increase the friction. Unfortunately that also caused the roller to really distort the tire and it was losing a lot of efficiency.
I decided to try a chain drive to replace the friction drive.
I knew I was losing some rpm but I got lost trying to calculate how much so I went ahead and built up a chain drive setup.
Lathing more Trex decking and a using a small cog from a 5 speed gear cluster resulted in this:
End result... not enough rpm.
I jumped ship on the scooter motor and went to a treadmill motor. It's flywheel has a built in fan and with the stock spring of the trainer I've seen around 100 watts from it.
The UPS is an APC BACK-UPS PRO 650. Here's some of the guts and the face.
I ordered a couple Ghurd controllers and built one up soldering the LEDs in on the opposite side, added an 80 watt halogen light, a 12 muffin fan, a switch, and a male cigarette lighter plug.... drilled two holes for the LEDs and one for the halogen light... crammed it all in the front of the UPS and ended up with this:
Here's what the face looks like.
This is what I wanted to mark it up to look like.
This setup worked well enough and while I was working on the generator I'd hook this to the solar to control it's charge.
I made the mistake of wiring the + of the generator to the controller side of the switch. I did this so there would be no voltage present at the cigarette lighter plug when the switch was off. I fried something in the controller and needed to build the spare one up.
I moved the + of the generator to other side of the switch and added a diode to the cigarette lighter plug and all was well.
I didn't want the UPS's beeper on constantly so started to work on silencing it. I had already soldered in a temporary LED in parallel with the speaker in hopes I could have a "visual beep" to aid in cold starting the UPS and that worked.
The space is small where the beeper is situated and I wanted to try sticking a toothpick into it's output hole to try and silence it before I tried a more permanent fix.
I removed a few screws and was able to get the toothpick into the beeper but upon start up, I noticed a red LED on the UPS come on that usually didn't light up unless you had a low battery.
As I moved the UPS around to get a better view I shorted the PCB out on the metal frame of the UPS, saw a spark from somewhere on the PCB... DOH!
I removed the battery and hooked everything up again but when I pressed the start button all I got was a click from one of the relays.
I searched the PCB and found this:
It's a fuse that uses the board trace as a fuse. Some of you have probably seen this before... I never had.
I found some small stranded wire that tested out at around 4 amp before it blew so I soldered one in for a repair.
I hooked the battery up and pushed the power button and got a steady scream from the beeper... not good.
That's pretty much where the projects stands now.
The PCB has two of those fuses, one appears to be good and two 40 amp automotive fuses that are soldered in and those appear to be good.
The circuits are too confusing for me to trace because the board has circuits on both sides.
Newegg.com has a 400 watt inverter that goes on sale often for $19.99 shipped. I think I'll grab one of those and stick that, the Ghurd controller, and the battery in an old metal tool box I have.
